Note 5 - Convertible Debentures (Details Textual) - USD ($)
 1 Months Ended 3 Months Ended 12 Months Ended
Feb. 29, 2016
Feb. 16, 2016
Feb. 29, 2016
Aug. 31, 2015
Dec. 31, 2015
Jun. 30, 2016
Jun. 30, 2015
Series A Warrant [Member] | Thirty-Year Debentures [Member]              
Residual Fair Value of Warrants       $ 3,385,000      
Series A Warrant [Member] | Other Expense [Member]              
Derivative, Gain (Loss) on Derivative, Net $ (149,000)            
Series A Warrant [Member]              
Fair Value Assumptions, Expected Dividend Rate 0.00%            
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 8   $ 8 $ 13.60      
Warrant Expiration Period       5 years 182 days      
Fair Value Assumptions, Expected Term 5 years            
Fair Value Assumptions, Expected Volatility Rate 91.00%            
Fair Value Inputs, Discount Rate 1.20%            
Class of Warrant or Right, Outstanding       404,412   404,412  
Warrants [Member]              
Fair Value Assumptions, Expected Term     5 years        
Fair Value Assumptions, Expected Volatility Rate     91.00%        
Fair Value Inputs, Discount Rate     1.20%        
Series B Warrant [Member] | Thirty-Year Debentures [Member]              
Residual Fair Value of Warrants       $ 897,000      
Class of Warrant or Right, Cancelled During Period,Value           $ 159,000  
Series B Warrant [Member]              
Fair Value Assumptions, Expected Dividend Rate           0.00%  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights       606,618      
Class of Warrant or Right, Exercise Price of Warrants or Rights       $ 13.60      
Warrant Expiration Period       1 year 180 days      
Fair Value Assumptions, Expected Term           1 year 73 days  
Fair Value Assumptions, Expected Volatility Rate           88.00%  
Fair Value Inputs, Discount Rate           0.57%  
Warrants Not Settleable in Cash, Fair Value Disclosure   $ 25,000       $ 33,000  
Class of Warrant or Right, Outstanding       222,427   222,427  
Shares Issued for Cashless Exercise of Warrants   125,000       106,711  
Class of Warrant or Right, Cancelled During Period,Value   $ 159,000          
Convertible Debt [Member] | Debt Issuance Cost Allocated to Debt [Member]              
Debt Issuance Costs, Net $ 183,000   $ 183,000        
Convertible Debt [Member] | Debt Issuance Cost Allocated to Equity [Member]              
Debt Issuance Costs, Net 37,000   37,000        
Convertible Debt [Member]              
Debt Instrument, Face Amount $ 12,500,000   $ 12,500,000        
Debt Conversion, Convertible Shares 3,676,471   3,676,471        
Debt Instrument, Term     3 years        
Debt Instrument, Interest Rate, Stated Percentage 22.00%   22.00%        
Proceeds from Convertible Debt     $ 12,319,000        
Warrants Not Settleable in Cash, Fair Value Disclosure $ 4,434,000   4,434,000        
Convertible Debt 1,061,000   1,061,000        
Debt Instrument, Unamortized Discount $ 11,258,000   11,258,000        
Amortization of Debt Discount (Premium)           $ 1,407,000  
Amortization of Debt Issuance Costs           23,000  
Interest Expense           1,031,000  
Debentures, Beneficial Conversion Feature [Member]              
Debt Instrument, Convertible, Beneficial Conversion Feature     6,824,000        
Thirty-Year Debentures [Member]              
Class of Warrant or Right, Number of Securities Called by Warrants or Rights       1,102,942      
Debt Instrument, Term       30 years      
Proceeds from Convertible Debt       $ 4,720,000      
Convertible Debt       0      
Debt Instrument, Unamortized Discount       4,720,000      
Amortization of Debt Discount (Premium)   4,648,000       4,720,000  
Amortization of Debt Issuance Costs   $ 765,000       777,000  
Potential Proceed from Issuance of Convertible Debt       15,000,000      
Gross Proceeds from Convertible Debt       5,500,000   5,500,000  
Registration Payment Arrangement, Gains and Losses           1,100,000  
Registration Payment         $ 220,000    
Repayments of Debt     7,500,000     7,500,000  
Gain (Loss) on Extinguishment of Debt           $ (795,000)  
Payment After Approval of Authorities [Member]              
Potential Proceed from Issuance of Convertible Debt       9,500,000      
Thirty-Year Debentures, Beneficial Conversion Feature [Member]              
Debt Instrument, Convertible, Beneficial Conversion Feature       438,000      
Fair Value Assumptions, Expected Dividend Rate           0.00% 0.00%
Gross Proceeds from Financing Transaction     $ 15,000,000        
Stock Issued During Period, Shares, New Issues     735,294        
Sale of Stock, Price Per Share $ 3.40   $ 3.40        
Stock Issued During Period, Value, New Issues     $ 2,500,000     $ 2,464,000  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 3,529,412   3,529,412        
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 8   $ 8        
Warrant Expiration Period     5 years        
Number of Warrants, Percentage of Shares Issued or to Be Issued     80.00%        
Debt Issuance Costs, Net $ 220,000   $ 220,000     $ 160,000  
Period after Benchmark Reached     15 days        
Net Cash and Short-Term Investment Benchmark $ 2,100,000   $ 2,100,000        
Duration of Moving Average Price     20 days        
Percent of Stock Price     125.00%        
Consecutive Days of Weighted Average Trading Price     10 days        
Share Price $ 4   $ 4        
Fair Value Assumptions, Expected Term           5 years 5 years
Fair Value Assumptions, Expected Volatility Rate           80.00% 75.00%
Proceeds from Convertible Debt           $ 18,000,000
Convertible Debt           2,489,000  
Debt Instrument, Unamortized Discount           9,851,000  
Amortization of Debt Discount (Premium)           6,127,000
Amortization of Debt Issuance Costs           800,000
Interest Expense           1,864,000 14,000
Approval for Grant in Amount for Clinical Trial       $ 10,000,000      
Registration Payment Arrangement, Gains and Losses           (1,100,000)
Derivative, Gain (Loss) on Derivative, Net           3,395,000
Gain (Loss) on Extinguishment of Debt           $ (795,000)